Belgium has most overcrowded prisons in EU

Belgium also recently reported some 32 prison guards had tested positive for the virus. Four inmates also have the virus and another 53 were quarantined.

The figures, compiled in a report by the human rights watchdog Council of Europe, represents data from both 2018 and 2019.

In a statement, the Council of Europe Secretary General Marija Pejčinović Burić, said all possible measures need to be taken to protect both prison populations and prison staff.

"Prison administrations and all the relevant authorities should strive to resort to alternatives to deprivation of liberty," she said, on Tuesday (7 April).

The UK, Italy, France, Poland, and Spain also had the largest number of inmates aged 65 and over.

Michelle Bachelet, United Nations High Commissioner for Human Rights, has previously made similar comments.

"Authorities should examine ways to release those particularly vulnerable to Covid-19, among them older detainees and those who are sick, as well as low-risk offenders," she said in late March.

The issue has since roused political sensibilities in Spain, which has jailed nine Catalan leaders.

Spain's Supreme Court last week issued a warning to the Catalan Prison Boards not to temporarily release them during the period of Covid-19 confinement.

Diana Riba i Giner, a Spanish MEP with the Green party, is now asking the European Commission to investigate.

"The statement of the Spanish Supreme Court represents a breach of the separation of powers," she wrote in a letter addressed to EU justice commissioner Didier Reynders.

She said Catalan prisoners are entitled to regular temporary leave, for work or voluntary activity, under article 100.2 of Spain's law governing prison regulations.

Prison density in Catalonia stood at around 88 inmates per 100 available spots, compared to some 70 in the rest of Spain, according to the Council of Europe report.

When it comes to incarceration rates, notes the report, Lithuania ranks the top with 232 people jailed per 100,000 inhabitants, followed by the Czech Republic (203), Poland (190) and Slovakia (189).

The lowest incarceration rates were found in Finland (50), Netherlands (56) and Sweden at 60 per 100,000 inhabitants.